Does anyone have an references or explanation why Hydrogen usually has no Neutron ?
It's almost as if the Hydrogen we know is a kind of anti-isotope, with deuterium being the 'proper' version.unionised - 27-12-2017 at 11:59
Neutrons are not stable, and there were not many around when the hydrogen was formed.aga - 27-12-2017 at 12:15
Thanks for the answer.
Mmmm.
A bit of time has passed since then, plus they seem to appear in 'normal' numbers in other atoms, despite their instability.
If unstable, there would be very few by now.
I was about to ask about proof etc then googled it.
'neutron' seems to be a convenient way to explain mass.
I'll go research further - basically i don't believe what i've read from what those dudes 100 years back came up with, and even got a Nobel for.SWIM - 27-12-2017 at 21:10
Neutrons are unstable when free(1/2 life less than a day), but may or may not be stable in a nucleus depending on the Z-shell situation.
Beta emitters have unstable neutrons in the nucleus. chornedsnorkack - 28-12-2017 at 12:49
A simple answer: in nuclei, protons and neutrons stabilize each other. Go too far from the balance and the nucleus is beta radioactive or flies apart
altogether.
The exception here is the nucleus of one nucleon because here flying apart is not an option. Only one of the two isobars can be stable, as per
Mattauch rule, and it is proton.
[Edited on 28-12-2017 by chornedsnorkack]aga - 28-12-2017 at 13:48
So nobody has any references for their claims, including me.
Business as usual then: mucho research required.WangleSpong5000 - 28-12-2017 at 14:13
Imagine an Oxygen nucleus. 6 protons 6 neutrons yeah? Imagine it only consisted of protons which are all positively charged. Would the strong nuclear
force be strong enough to overpower the electrostatic force of the protons? It wouldn't be... the strong force operates over much smaller distances
than the other forces. Neutrons act as a kind of filler. The nucleus can exist because the strong force holds the whole thing together...
electrostatic force is not attracting neutrons to protons as they have no charge but the strong force holds them together (which has to do with with
the way the quarks interact... the strong force is redisdual 'color' force leakage of quark interaction) but electostatic repulsion would blow the
nucleus apart if there were no neutrons.
Notice how very heavy elements have a different proton to neutron ratio? It's 1 to 1 for most elements. its about 1 to 1.5 for really heavy elements.
This is because the nucleus in these cases contains lots of protons and needs even more than 1 proton per neutron to be stable. And they often arent
stable...
Hydrogen is just a combination of quarks. It could exist on its own as it was stable on its own. it coulsnt blow itslef apart electrostatically as it
is only a single particle and I suppose the configuration of the quarks that made it was favourable... wg48 - 29-12-2017 at 05:22
So nobody has any references for their claims, including me.
Business as usual then: mucho research required.
Not really mucho research if you Google "why so little deuterium in the early universe"
But just in case your google is broken the short answer is:
As the early universe cooled part of the particle soup decayed to protons and less neutrons. The neutrons combined with the protons to form mostly
deuterium nuclei, and helium nuclei. Most of the deuterium was very quickly (minutes) converted to mostly helium nuclei in various reactions by which
time the universe had cooled such that most of the nuclear reactions stopped. Leaving mostly hydrogen and helium. (the prevailing view)
chornedsnorkack - 29-12-2017 at 10:50
There is a simpler explanation, which does not go deep into early universe.
Deuterium is stable - barely. It has no excited states. And it has second lowest binding energy of all stable nuclei.
Sun produces a lot of deuterium. Most of sunlight comes from deuterium...
except the deuterium does not last. The lifetime of proton in the centre of Sun is around 10 milliards of years. The lifetime of deuteron there is 2
seconds.
Either the conditions favour fission (low density), and then it goes past deuteron to protons, or else they favour fusion (high density) and then
fusion goes rapidly past deuterium to helium or beyond. It is always easier to destroy deuterium than create it.sclarenonz - 29-12-2017 at 11:17
Really, this question has never confused me. I am quite happy with the idea that the relative frequencies of isotopes is a function of their
stability. Protons last nearly forever. Deuterium not so much: especially in conditions that enable fusion.WangleSpong5000 - 29-12-2017 at 17:44
So nobody has any references for their claims, including me.
Business as usual then: mucho research required.
Internet... lol
No I actually knew all that stuff I said already... yeah nah ... more like 25% ... possibly. I found a particularly good explanation on the the google
machine. I'll go into my history and post it up after I've recovered from the new year...
